HaloIPT’s wireless charging systems use inductive power transfer (IPT) to transfer power over gaps of up to 400mm (15.75 inches) and are tolerant to parking misalignment with power transfer efficiencies that can match a plug-and-cable. The company is currently delivering units in the range 3 to 7kW and is also developing higher power 3-phase systems for public charging.

IPT systems work by taking electrical power from the grid and energizing a coil (the primary coil), with current typically in the range 5-125A. The coil is inductive; compensation using series or parallel capacitors may be required to reduce the working voltages and currents in the supply circuitry. Pick-up coils are magnetically coupled to the primary coil. Power is transferred by tuning the pick-up coil to the operating frequency of the primary coil with a series or parallel capacitor. The power transfer is controllable with a switch-mode controller.

A high-frequency generator or power supply. The high-frequency generator takes voltage input (240VAC at 50/60Hz) and produces a high-frequency (>20kHz) current. The output current is controlled and the generator may be operated without a load. The efficiency of the generator is greater than 94% at 2kW.
The generator comprises a filter (to reduce EMI); rectifier; bridge (MOSFETs) converting DC to high frequency; combined isolating transformer /AC inductor; tuning capacitors (specified for frequency and output current); and control electronics (microcontroller, digital logic, feedback and protection circuits).

A magnetic coupling system or transmitter/receiver pads. The coupling circuits are tuned through the addition of compensation capacitors. The pad construction provides shielding of magnetic fields to prevent EMI within the vehicle and ensures levels of MF exposure are within suggested international guidelines (ICNIRP).

A pick-up controller/compensation. The pickup controller takes power from the receiver pad and provides a controlled output to the batteries, typically ranging from 250V to 400V DC. The controller provides an output that remains independent of the load and the separation between pads. Without a controller, the voltage would rise as the gap decreased and fall as the load current increased.

The main components in the pickup controller are: tuning capacitors; transistors (MOSFETs) for power control and protection; rectifier; DC inductor; capacitors to smooth output voltage; and control circuit, including sensors for voltage and current.

HaloIPT’s system is battery-agnostic; the pick-up controller interfaces directly with the proprietary battery management system on the vehicle.

Mains voltage input is filtered prior to rectification,
using a full-bridge rectifier. The H-bridge drives the primary
side of a transformer via a DC blocking capacitor
Cb, which prevents DC current flow in the transformer
primary. The output of the transformer is tuned with capacitor
C1 driving the primary pad, L1, which is magnetically
coupled to the secondary pad, L2, with a mutual
inductance M.

The secondary pad L2 is tuned with capacitor C2 and
its output drives a controllable rectifier producing DC
output. The rectifier’s output, is filtered using inductor Lout
and capacitor Cout to obtain the output voltage Vout
used to charge the battery.

Sensors are used to measure the battery voltage and
current as required for the charging process. A CANBus
interface is connected to the BMS and ECU for control
and feedback purposes.

Source: HaloIPT. Click to enlarge.

We are delighted to provide our wireless charging technology for this trial. Industry feedback so far tells us that the automation advantages of wireless charging make it the best charging solution for luxury electric vehicles and will be the key to unlocking the potential of this exciting market. Users don’t need to get out of their vehicles and hunt for a cable to plug-in, they will just park and walk away while their car starts charging automatically … the ultimate in modern convenience.

—Dr Anthony Thomson, CEO of HaloIPT

The technology is designed to function beneath asphalt, and works under water or covered in ice and snow. IPT systems can be configured to work with all road-based vehicles from small city cars to heavy-goods vehicles and buses. With IPT technology embedded into roads, cars could also be charged on the move. This dynamic in-motion charging would reduce battery size requirements as well as providing charging convenience, the company suggests.

HaloIPT is a technology development company founded by Auckland
UniServices (NZ) and Arup (UK).

Comments

Great stuff. I have never been a fan of huge battery pack, as you end up lugging around more and more weight and recharging times become a progressively bigger issue.
The Rolls pack is only rated for 3 years.
It is for that reason that I am a fan of fuel cells, but this system could do even better, and although expensive to install in roads might eventually mean that cars could be really light.
This is also far more practical for roadside use than cables trailing around.

When embedded into parking places, garage floors etc such charging system could be completely invisible and without human intervention. Power used could be electronically and automatically charged to users bank account or credit/debit cards.

The ideal would be to have embedded charging systems into selected highway segments to pick power while driving and reduce the charging stops frequency, even with smaller batteries. That would really put an end to all liquid fuel vehicles.

"...with power transfer efficiencies that can match a plug-and-cable..."

If they have to resort to known lies to promote their product, how ever good, they should be ignored for a while longer; every coil, rectifier, capacitor and transistor has losses that a plug and wire does not have.

People eventually have to get out of car and get into them. Expensive luxury automobiles have delayed the advent of cheap plug in hybrid automobiles by diverting money and talent to $200,000 automobiles. Batteries can be paid for by leasing them from power companies when the capital costs are high.

The capital costs of refineries and gasoline distribution is very high but it does not have to be paid ten years in advance.

With a slight modification of processes, France could produce enough Plutonium 238 to power both an automobile and a small aircraft for the president of the country that need never to be refueled. A mountain of plutonium 238 might glow red hot and melt but it would never explode. The vehicles can run for over a hundred years without stopping, but they can feed power into the grid when stopped.

Other cheaper radio isotopes can provide heat to warm buildings with more statistical safety than natural gas.

Plug and wire systems for charging vehicles use many of the same components found in Inductive systems...especially charging systems with Mode 3 safety protection and higher power levels. They too need coils, rectifiers, isolating transformers, and lengths of copper all with inherent losses. No transfer of power be it wired or wireless is 100% efficient and many of the plug and wire systems available quote wall-to-battery efficiencies south of Inductive systems!

For sceptics, a quick trip to Turin or Genoa, in Italy, to ride on a bus charged by Induction would be worthwhile. These buses are very REAL and have been operating successfully for over 10 years. The buses (40 in total) receive a top-up each time they stop to pick-up/drop-off passengers. The system is rated at 60kW and operates at 90% total system efficiency.

Note that they are bypassing the car's built-in charger, typically 85-92% efficient.. so they spend a bit more effort (with a sophisticated booster) to compensate for the wireless losses and end up with better overall efficiency.